Smooth vertices option not working in blender 2.82
I am not sure if this is what you have done, but I recently was trying to add weight to all objects and nothing worked and that was due to a selection mask being selected yet no objects selected. In Sculpt Mode the following picture shows how I can smooth any object



In the following picture only the selected stroke is edited. If, like me, you don't have any strokes selected, then you will not be able to edit.